Improvement in the manufacture of door-knobs



' 2SheetsSheet1.. J. P. ADAMS. MANUFACTURE OF DOOR KNOBS. No.179,540. Patented J'u1y11,1876.

2 S'heets-Sheet Z.

J. P. ADAMS. MANUFACTURE OF DOOR KNOBS" v No. 179,640, .Patented J'u1y11,1876.

UNITED STATES 11-;

'r FFICE.

JOHN P. ADAMS, OF BROOKLYN, ASSIGNOR OF ONE- HALF HIS RIGHT TO JAMES A. RUTHVEN, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFACTURE OF DOOR-KNOBS.

Specification forming part of Letters Patent No. 179,640, dated July 11, 1876; application filed August-i, 1874.

To all whom it may concern:

Be it known that I, JOHN POPKIN ADAMS, of Brooklyn, in the county of Kings and'State of New York, have made an invention of certain new and useful Improvements in the Manufacture of Knobs for Door-Locks and similar purposes; and that the following is a full, clear, and exact description and specification of the same. The object of my invention is, mainly, to produce a strong metal-shanked knob at alow cost; and to this end my invention consists of certaincombinations of the following mechanical devices, viz: a ball of a low-priced material-such, for example, as wood or othersuitable material which will not withstand a high temperature; a shank of metal fusible at so low a temperature that it may be cast fast to wood; a shankdining of hard sheet metal; and a continuous coveri ngof metal, either plain or ornament a1, applied in various ways. My invention consists, further, of the process of combining the shank with the ball of the knob by casting the former fast to the latter. One or more parts of my invention may be used separately from the others; but in order that my invention maybe fully understood, I have represented in the accompanying drawing, and will proceed to describe, a door-knob embodying all parts of my invention in a good form for practical use, and also the system by which I have manufactured such a knob.

In the said drawings, Figure 1 represents a side view of the said knob. Fig. 2 represents :a central longitudinal section of the same. Figs. 3 and 4 represent central sections of the ball of the knob before and after being covered. Fig. 5 represents a section of a mold, such as used in the manufacture of such knobs. Fig. 6 is a top view of the same. Fig. 7 is a perspective view of the lining of the shank.

The knob represented in said drawings is composed of a solid wooden core or ball, A, of a continuous metal cover, B, for the ball, of a shank, O, of fusible metal, (by which term I mean metal that will fuse at so low a temperature that it will not injure the ball when cast in contact with it,) and of a shank-lining, m. The ball A has a socket, d, Fig. 3, formed in its inner face to admit the metal of the shank;

and this socket is made convergent, or of smaller diameter at its mouth than at its bottom in the ball, so that the shank, after casting and cooling, is locked by the engagement of a divergent portion of the shank in the convergent socket of the shank in the cavity of the ball, whereby the ball is held from being pulled oii" of the shank. Holes 0 c, Fig. 3, are formed in the wooden ball, so that the melted metal of the shank may flow into them and cool therein in the form of pins, which will compel the shank to .turn with the ball when the knob is in use. These holes for the castmetal pins. may be boreddiverging, or may be screwed, so that the divergence or the screwed form of the pins effectsthe locking of the cast metal to the ball, and also prevents the hall from turning independently of the shank. The covering of the ball with a continuous metal cover, B, may be effected by spinning or by projection that enters the shank-socket, and

to which the ball is secured by a screw or otherwise, so as to hold the ball centrally in the mold. Then melted fusible metal is poured into the gate of the mold, so as to envelop the ball up to the mouth of the shank-socket. The mold may have an ornamental contour, the counterpart of that to be imparted to the knob.

' In case the cover is to be applied partly by spinning and partly by casting, a cover of sheet metal is lirst spun over the ball, after which the cover is coated with a flux and placed in a two-part mold, which, if the knob is to be ornamented with figures, is the counterpart of the ornamental configuration to be formed upon the'surface of the knob, and then fusible metal is cast into the mold and unites with the metal of the spun cover.

The cover produced by each of the above modes is in one piece, entirely surrounding the ball up to the junction of the ball and shank G, and is, therefore, continuous.

The shank of the knob, whether the ball is to be of uncovered wood, or has been covered with metal by either of the modes above mentioned, is combined with the ball by casting it fast thereto in the following manner: A metal mold, such as is represented at Figs. 5 and 6, is provided. This mold is composed of five principal parts-viz., the socket-piece G, the two filling-pieces H H, which fill the mouth of the socket over the ball, and form the matrix for the shank, and the two closingpieces J J, which close the top of the mold and sustain the metal core I, which forms the cavity for the knob-spindle. The mold is formed with gates or orifices for the pouring in of the melted metal and the escape of air. The ball is set into the mold, the latter is closed, and the melted metal is poured in. When the metal has become set, the spindleoore is drawn out by means of an eccentric lever, K, with which it is connected, and the mold is opened and turned upside down, to permit the knob todrop out, after which a new knob may be completed in like manner. If the ball has been covered, the rim of the opening of the cover at the mouth of the shank-socket should be coated with a flux, so as to secure the union of the metal of the shank with that of the cover.

After the shank has been cast, the knob may be finished in any expedient manner. Thus, the shank may be turned smooth and burnished. 1f the ball be of uncovered wood,

it may be varnished, and if it be a covered ball the cover, if plain, may be burnished; or the covered knob may be plated, or electrotyped, or .bronzed, or otherwise finished, as metal knobs of other constructions are.

The knob, when completed, has all the characteristics and advantages of one of solid metal, while it is of much lighter weight, and the cost at which it can be produced is greatly less than that of such a knob. Wood is used as the material for the core or ball, because it can be turned or produced by machinery at a trifling cost, and because it shrinks when the hot metal is cast upon it about enough to compensate for the shrinkage of the metal in cooling, so that the cover, when cast, does not split in cooling.

An essential feature of my invention is the casting of the shank fast to the ball pre viously prepared, so that a part of the metal of the shank engages with the ball, and the fusible metal, which I have used with success for the shank, is one composed by melting together seventy-five parts, by weight, of tin, fifteen parts of copper, and ten parts of antimony. The same compound is also a suitable one for a spun cover. As this metal is soft, and not well adapted to sustain strains incidental to the play of the knob on the knobspindle, a lining, m, of hard sheet metal, such as sheet-brass, is bent into the form of a square tube of the proper size to receive the knobspindle, and is placed in the mold over the spindle-core before casting the shank. The

surface of this lining should be tinned and coated with a flux, so as to cause the metal of the shank to combine solidly with the lining.

I am aware that a knob has been formed with a shank of fusible metal by casting the shank separately from the knob, and by driving the cast shank into a cavity in the knob; but in such case the metal of the shank is held to the ball only by frictional contact, and not byinterlooking it in a convergent cavity of the ball.

I am also aware that a knob made in one piece with a neck or shank has had a socketed base or shoe of metal cast about the foot of the neck of the knob, and containing sometimes a hard-metal collet; but in such cases the cast metal did not form the neck or shank of the knob, and was not interlocked in a socket in the ball, and the collet did not extend into the neck of the knob. I am also aware that knobs have been covered with sheet metal; but in such case the cover was formed of two cups connected at the greatest diameter of the knob, instead of in a single piece, forming a continuous cover, surrounding the knob up to the shank; moreover, the metal of the shank did not interlock in a socket of the knob-ball. I am also aware that balls with shanks of low-priced metal, such as iron, have had the surfaces of the ball and shank simultaneously covered with a covering'of cast metal. I therefore do not claim a ball of wood; nor the combination of one in every manner with a shank of metal; nor the covering of a knob of wood, or of a knob and shank of metal, with a sheet or cast metal cover; nor a shank of fusible metal connected in every way with a ball; nor a cup or shoe of fusible metal cast upon the foot of a knob neck or shank, or upon or about a part of the knob.

What I claim as my invention is 1. The combination, substantially as before set forth, of the ball and a shank of fusible metal, a divergent portion of which is locked in a convergentsocket of the ball.

2. The combination, substantially as before 4. The combination, substantially as before set forth, of the fusible-metal knob-shank and the hard sheet-metal lining extended into the portion thereof which acts as a neck for the knob.

5. The combination, substantially as before set forth, of the knob-ball, the fusible-metal knob-shank, the sheet-metal lining for the said shank, and the continuous metal covering for the ball.

6. The improvement in the art of mannfacwithout a shank or neck; secondly, the coverturing knobs, substantially-as before set forth, ing' of the shankless ball with metal; and, consisting of, first, the formation of the ball thirdly, the formation of the shank and the (without a neck or shank) with a convergent union of it with the ball and cover by casting socket, and, secondly, of the simultaneous said shank fast to said ball and cover. formation of the shank and the union of it Vvitness my hand this 11th day of July, with the ball by casting said shank partially A. D. 1874. 7

into the convergent socket of the ball. JOHN POPKIN ADAMS.

7. The improvement in the artof mannfac- Witnesses:

turing' knobs, substantially as before set forth, M. S. THOMPSON,

consisting of, first, the formation of a ball CHAS. GEO. Ross. 

